Dec. 1 (Bloomberg) -- Monsanto Co. corn that is genetically engineered to kill insects may be losing effectiveness against rootworms in four states, the U.S. Environmental Protection Agency said.
Rootworms in Iowa, Illinois, Minnesota and Nebraska are suspected of developing tolerance of the plants’ insecticide, based on documented cases of severe crop damage and reports from entomologists, the EPA said in a document dated Nov. 22 and posted yesterday on the government website. Monsanto’s program for monitoring suspected cases of resistance is “inadequate,” the EPA said.
An Iowa State University study said in July that some rootworms have evolved resistance to an insect-killing protein derived from Bacillus thuringiensis, or Bt, a natural insecticide engineered into Monsanto corn. Entomologists in Illinois and other Midwestern states are studying possible resistance where the insects devour roots in Monsanto’s Bt corn.
“Resistance is suspected in at least some portions of four states in which ‘unexpected damage’ reports originated,” the EPA said in the document, an internal memo that reviewed damage reports.
There is no scientific confirmation of resistance to Monsanto’s Bt corn, Lee Quarles, a spokesman for the St. Louis- based company, said today by telephone. Monsanto takes the EPA report “seriously” and is increasing efforts to teach farmers how to respond to unexpected damage in their fields, he said.
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